I was wondering if it was possible to use the External Sync Input to record capture times from other devices? For example, maybe an external sensor data frame capture sends a TTL to the External Sync Input. Instead of using the input to control the cameras, maybe it can just recorded in the output of the data export for that capture?

The Camera SDK has full support for synchronizing cameras with an external device, but you would probably not have access to recording the sync signal or its duration duration.http://optitrack.com/products/camera-sdk/